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[texts]String Theory - J. L. F. Barbon
This is a rendering of a review talk on the state of String Theory, given at the EPS-2003 Conference, intended for a wide audience of experimental and theoretical physicists. It emphasizes general ideas rather than technical aspects.
Downloads: 48 4.00 out of 5 stars4.00 out of 5 stars4.00 out of 5 stars4.00 out of 5 stars(1 review)
[texts]Causal set as a discretized phase spacetime - Roman Sverdlov
The first goal of this paper is to show that discreteness, locality, and relativistic covariance can peacefully coexist if the ordinary spacetime (OST) is replaced with phase spacetime (PST) as a geometric background of a Poisson process, where PST is a spacetime generalization of a notion of phase space (this is a 7-dimensional version of the 8-dimensional structure proposed by Caianiello). Furthermore, Caianiello's idea of finite acceleration is implemented...
Downloads: 26 4.00 out of 5 stars4.00 out of 5 stars4.00 out of 5 stars4.00 out of 5 stars(1 review)
[texts]Chronon corrections to the Dirac equation - Andrei A. Galiautdinov
The Dirac equation is not semisimple. We therefore regard it as a contraction of a simpler decontracted theory. The decontracted theory is necessarily purely algebraic and non-local. In one simple model the algebra is a Clifford algebra with 6N generators. The quantum imaginary $\hbar i$ is the contraction of a dynamical variable whose back-reaction provides the Dirac mass. The simplified Dirac equation is exactly Lorentz invariant but its symmetry group is SO(3,3), a decontraction of the Poinca...
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[texts]Witten-Nester Energy in Topologically Massive Gravity - Ergin Sezgin
We formulate topologically massive supergravity with cosmological constant in the first order formalism, and construct the Noether supercurrent and superpotential associated with its local supersymmetry. Using these results, we construct in ordinary topologically massive gravity the Witten-Nester integral for conserved charges containing spinors which satisfy a generalized version of Witten equation on the initial value surface...
Downloads: 2
[texts]The absorption spectrum of V838 Mon in 2002 February - March. I. Atmospheric parameters and iron abundance - B. M. Kaminsky
We present a determination of the effective temperatures, iron abundances, and microturbulent velocities for the pseudophotosphere of V838 Mon on 2002 February 25, and March 2 and 26. Physical parameters of the line forming region were obtained in the framework of a self-consistent approach, using fits of synthetic spectra to observed spectra in the wavelength range 5500-6700A. We obtained Tef = 5330, 5540 and 4960 K, for February 25, March 2, and March 26, respectively...
Downloads: 2
[texts]MSW effect with flavor changing interactions and the atmospheric neutrino problem - J. C. Montero
We consider flavor changing effective neutrino interactions in the context of massive neutrinos in the issue of atmospheric neutrinos. Assuming as usual that this is an indication of the oscillation of muon neutrinos into tau neutrinos we show that there is a set of parameters which is consistent with the MSW resonance condition for the typical Earth density and atmospheric neutrino energies. In particular we show that even if the vacuum mixing angle vanishes it is still possible to have a reson...
[texts]Precise Measurement of Gravity Variations During a Total Solar Eclipse - Qian-shen Wang
The variations of gravity were measured with a high precision LaCoste-Romberg D gravimeter during a total solar eclipse to investigate the effect of solar eclipse on the gravitational field. The observed anomaly $(7.0 \pm 2.7) \times 10^{-8}$ m/s$^2$ during the eclipse implies that there may be a shielding property of gravitation.
Downloads: 2
[texts]Hyperon-nucleon force from lattice QCD - H. Nemura
We calculate potentials between a proton and a $\Xi^0$ (hyperon with strangeness -2) through the equal-time Bethe-Salpeter wave function, employing quenched lattice QCD simulations with the plaquette gauge action and the Wilson quark action on (4.5 fm)^4 lattice at the lattice spacing $a \simeq 0.14$ fm. The ud quark mass in our study corresponds to $m_{\pi}\simeq 0.37$ and 0.51 GeV, while the s quark mass corresponds to the physical value of $m_K$...
[texts]arxiv-1206.4117
[texts]Lensless ghost imaging with true thermal light - Xi-Hao Chen
We report the first (to our knowledge) experimental demonstration of lensless ghost imaging with true thermal light. Although there is no magnification, the method is suitable for all wavelengths and so may find special applications in cases where it is not possible to use lenses, such as with x-rays or gamma-rays. We also show numerically that some magnification may be realized away from the focal plane, but the image will always be somewhat blurred.
Downloads: 3
[texts]A change of variable formula with Itô correction term - Krzysztof Burdzy
We consider the solution $u(x,t)$ to a stochastic heat equation. For fixed $x$, the process $F(t)=u(x,t)$ has a nontrivial quartic variation. It follows that $F$ is not a semimartingale, so a stochastic integral with respect to $F$ cannot be defined in the classical It\^{o} sense. We show that for sufficiently differentiable functions $g(x,t)$, a stochastic integral $\int g(F(t),t)\,dF(t)$ exists as a limit of discrete, midpoint-style Riemann sums, where the limit is taken in distribution in the...
Downloads: 1
[texts]Sky Subtraction with Fiber-Spectrographs - C. Lissandrini
The sky subtraction performances of multi-fiber spectrographs are discussed, analysing in detail the case of the OPTOPUS system at the 3.6 meter ESO telescope at La Silla. A standard technique, based on flat-fields obtained with a uniformly illuminated screen on the dome, provides poor results. A new method has been developed, using the [OI] emission line at 5577 \AA\ as a calibrator of the fiber transmittance, taking into account the diffuse light and the influence of each fiber on the adjacent...
Downloads: 4
[texts]Macroscopic two-state systems in trapped atomic condensates - Dmitry Solenov
We consider a macroscopic two-sate system based on persistent current states of a Bose-Einstein condensate (BEC) of interacting neutral atoms confined in a ring with a weak Josephson link. We demonstrate that macroscopic superpositions of different BEC flows are energetically favorable in this system. Moreover, a macroscopic two-state dynamics emerges in the low energy limit. We also investigate fundamental limitations due to the noise inherent to the interacting BEC of Josephson-ring geometry...
[texts]Two-pion exchange potential and the $πN$ amplitude - M. T. Peña
We discuss the two-pion exchange potential which emerges from a box diagram with one nucleon (the spectator) restricted to its mass shell, and the other nucleon line replaced by a subtracted, covariant $\pi N$ scattering amplitude which includes $\Delta$, Roper, and $D_{13}$ isobars, as well as contact terms and off-shell (non-pole) dressed nucleon terms. The $\pi N$ amplitude satisfies chiral symmetry constraints and fits $\pi N$ data below $\sim$ 700 MeV pion energy...
Downloads: 1
[texts]WASP-54b, WASP-56b and WASP-57b: Three new sub-Jupiter mass planets from SuperWASP - F. Faedi
We present three newly discovered sub-Jupiter mass planets from the SuperWASP survey: WASP-54b is a heavily bloated planet of mass 0.636$^{+0.025}_{-0.024}$ \mj and radius 1.653$^{+0.090}_{-0.083}$ \rj. It orbits a F9 star, evolving off the main sequence, every 3.69 days. Our MCMC fit of the system yields a slightly eccentric orbit ($e=0.067^{+0.033}_{-0.025}$) for WASP-54b. We investigated further the veracity of our detection of the eccentric orbit for WASP-54b, and we find that it could be re...
Downloads: 3
[texts]Chemical Evolution models of Local Group galaxies - M. Tosi
Status quo and perspectives of standard chemical evolution models of Local Group galaxies are summarized, discussing what we have learnt from them, what we know we have not learnt yet, and what I think we will learn in the near future. It is described how Galactic chemical evolution models have helped showing that: i) stringent constraints on primordial nucleosynthesis can be derived from the observed Galactic abundances of the light elements, ii) the Milky Way has been accreting external gas fr...
Downloads: 2
[texts]Reducing systems for very small trees - Patrick Reynolds
We study very small trees from the point of view of reducing systems of free factors, which are analogues of reducing systems of curves for a surface lamination; a non-trivial, proper free factor $F \leq \FN$ reduces $T$ if and only if $F$ acts on some subtree of $T$ with dense orbits. We characterize those trees, called arational, which do not admit a reduction by any free factor: $T$ is arational if and only if either $T$ is free and indecomposable or $T$ is dual to a surface with one boundary...
[texts]Equilibration and aging of dense soft-sphere glass-forming liquids - Luis Enrique Sanchez-Diaz
The recently-developed non-equilibrium extension of the self-consistent generalized Langevin equation theory of irreversible relaxation [Phys. Rev. E (2010) 82, 061503; ibid. 061504] is applied to the description of the irreversible process of equilibration and aging of a glass-forming soft-sphere liquid that follows a sudden temperature quench, within the constraint that the local mean particle density remains uniform and constant...
[texts]Generalized Phase Rules - Akira Shimizu
For a multi-component system, general formulas are derived for the dimension of a coexisting region in the phase diagram in various state spaces.
Downloads: 1
[texts]Scaling of Seismic Memory with Earthquake Size - Zeyu Zheng
It has been observed that the earthquake events possess short-term memory, i.e. that events occurring in a particular location are dependent on the short history of that location. We conduct an analysis to see whether real-time earthquake data also possess long-term memory and, if so, whether such autocorrelations depend on the size of earthquakes within close spatiotemporal proximity. We analyze the seismic waveform database recorded by 64 stations in Japan, including the 2011 "Great East Japan...
Downloads: 4
[texts]Cosmology of Gravitino LSP Scenario with Right-Handed Sneutrino NLSP - Koji Ishiwata
We consider supersymmetric model with right-handed (s)neutrinos where the neutrino masses are purely Dirac-type. We discuss cosmology based on such a scenario, paying particular attention to the case that the gravitino is the lightest superparticles (LSP) while the right-handed sneutrino is the next-LSP. It will be shown that the cosmological constraints on the gravitino-LSP scenario (in particular, those from the big-bang nucleosynthesis) are drastically relaxed in such a case...
Downloads: 1
[texts]Test of charge conjugation invariance in the decay of the eta meson into pi(+)pi(-)pi(0) - M. Zielinski
In this work we present the preliminary results of the analysis of the pp->pp eta(->pp pi(+)pi(-)pi(0) reaction aiming to test the charge conjugation symmetry C in strong interactions. Based on approximately $10^5$ identified eta->pi(+)pi(-)pi(0) decay events we have extracted asymmetry parameters sensitive to C symmetry violation for different isospin values of the final state and we have established that all are consistent with zero within the obtained accuracy.
Downloads: 3
[texts]Analysis of a Fragmenting Sunspot using Hinode Observations - Rohan E. Louis
We employ high resolution filtergrams and polarimetric measurements from Hinode to follow the evolution of a sunspot for eight days starting on June 28, 2007. The imaging data were corrected for intensity gradients, projection effects, and instrumental stray light prior to the analysis. The observations show the formation of a light bridge at one corner of the sunspot by a slow intrusion of neighbouring penumbral filaments...
Downloads: 2
[texts]CP violation in top pair production at an e^+e^- collider - Darwin Chang
We investigate a possible CP violating effect in $e^+e^-$ annihilation into $t\bar t$ top quark pairs. As an illustrative example, we assume the source of the CP nonconservation is in the Yukawa couplings of a neutral Higgs boson which contain both scalar and pseudoscalar pieces. One of the interesting observable effects is the difference in production rates between the two CP conjugate polarized $t\bar t$ states.
Downloads: 2
[texts]arxiv-astro-ph9808315
[texts]Matching four-point functions in higher spin AdS_3/CFT_2 - Eliot Hijano
Working in the context of the proposed duality between 3D higher spin gravity and 2D W_N minimal model CFTs, we compute a class of four-point functions in the bulk and on the boundary, and demonstrate precise agreement between them. This is the first computation of a correlator in 3D higher spin gravity whose functional form is not fixed by conformal invariance. In the bulk we make use of elegant methods to solve the scalar field equation using only matrix manipulations, while on the CFT side we...
Downloads: 2
[texts]Families that remain $k$-Sperner even after omitting an element of their ground set - Balazs Patkos
A family $\cF\subseteq 2^{[n]}$ of sets is said to be $l$-trace $k$-Sperner if for any $l$-subset $L \subset [n]$ the family $\cF|_L=\{F|_L:F \in \cF\}=\{F \cap L: F \in \cF\}$ is $k$-Sperner, i.e. does not contain any chain of length $k+1$. The maximum size that an $l$-trace $k$-Sperner family $\cF \subseteq 2^{[n]}$ can have is denoted by $f(n,k,l)$. For pairs of integers $l
Downloads: 2
[texts]arxiv-1206.3184
[texts]A variable near-infrared counterpart to the neutron-star low-mass X-ray binary 4U 1705-440 - Jeroen Homan
We report the discovery of a near-infrared (nIR) counterpart to the persistent neutron-star low-mass X-ray binary 4U 1705-440, at a location consistent with its recently determined Chandra X-ray position. The nIR source is highly variable, with K_s-band magnitudes varying between 15.2 and 17.3 and additional J- and H-band observations revealing color variations. A comparison with contemporaneous X-ray monitoring observations shows that the nIR brightness correlates well with X-ray flux and X-ray...
Downloads: 2
[texts]Statistical mechanics of confined binary system: Comparison of three and two dimensions - Ali Nayeri
We have used a toy model to study the behaviour of confined binary systems in 2$D$ and compare it with previously known result in 3$D$. In the case of 2$D$, in which canonical distribution exists only above a critical temperature, we evaluate the exact form of partition function for this system and compare the exact partition function with the mean field partition function for the case of two-particle system...
Downloads: 3
[texts]Disorder-Induced First Order Transition and Curie Temperature Lowering in Ferromagnatic Manganites - J. Salafranca
We study the effect that size disorder in the cations surrounding manganese ions has on the magnetic properties of manganites. This disorder is mimic with a proper distribution of spatially disordered Manganese energies. Both, the Curie temperature and the order of the transition are strongly affected by disorder. For moderate disorder the Curie temperature decreases linearly with the the variance of the distribution of the manganese site energies, and for a disorder comparable to that present i...
Downloads: 2
[texts]Motivic Milnor fiber of cyclic L-infinity algebras - Yunfeng Jiang
We define motivic Milnor fiber of cyclic $L_\infty$-algebras of dimension three using the method of Denef and Loeser of motivic integration. It is proved by Nicaise and Sebag that the topological Euler characteristic of the motivic Milnor fiber is equal to the Euler characteristic of the \'{e}tale cohomology of the analytic Milnor fiber. We prove that the value of Behrend function on the germ moduli space determined by $L$ is equal to the Euler characteristic of the analytic Milnor fiber...
Downloads: 2
[texts]Stability of blow-up profile and lower bounds for blow-up rate for the critical generalized KdV equation - Yvan Martel
The generalized Korteweg-de Vries equations are a class of Hamiltonian systems in infinite dimension derived from the KdV equation where the quadratic term is replaced by a higher order power term. These equations have two conservation laws in the energy space H^1(L^2 norm and energy). We consider in this paper the {\it critical} generalized KdV equation, which corresponds to the smallest power of the nonlinearity such that the two conservation laws do not imply a bound in H^1 uniform in time fo...
[texts]Hamilton-Jacobi quantization of the finite dimensional systems with constraints - Dumitru Baleanu
The Hamiltonian treatment of constrained systems in $G\ddot{u}ler's$ formalism leads us to the total differential equations in many variables. These equations are integrable if the corresponding system of partial differential equations is a Jacobi system. The main aim of this paper is to investigate the quantization of the finite dimensional systems with constraints using the canonical formalism introduced by $G\ddot{u}ler$...
[texts]Natural Quark Mass Patterns - K. Wang
We incorporate the idea of natural mass matrices into the construction of phenomenologically viable quark mass matrix patterns. The general texture pattern for natural Hermitian mass matrices is obtained and several applications of this result are made.
Downloads: 1
[texts]Interpretation of Solar Magnetic Field Strength Observations - R. K. Ulrich
This study based on longitudinal Zeeman effect magnetograms and spectral line scans investigates the dependence of solar surface magnetic fields on the spectral line used and the way the line is sampled in order to estimate the magnetic flux emerging above the solar atmosphere and penetrating to the corona from magnetograms of the Mt. Wilson 150-foot tower synoptic program (MWO). We have compared the synoptic program \lambda5250\AA line of Fe I to the line of Fe I at \lambda5233\AA since this la...
Downloads: 2
[texts]Classification spaces of maps in model categories - Daniel Dugger
This paper corrects a small mistake in a paper of Dwyer-Kan, and uses this to identify homotopy function complexes in a model category with the nerves of certain categories of zig-zags.
Downloads: 3
[texts]A Uniform Fixpoint Approach to the Implementation of Inference Methods for Deductive Databases - Andreas Behrend
Within the research area of deductive databases three different database tasks have been deeply investigated: query evaluation, update propagation and view updating. Over the last thirty years various inference mechanisms have been proposed for realizing these main functionalities of a rule-based system. However, these inference mechanisms have been rarely used in commercial DB systems until now. One important reason for this is the lack of a uniform approach well-suited for implementation in an...
Downloads: 2
[texts]Missing Power vs low-l Alignments in the Cosmic Microwave Background: No Correlation in the Standard Cosmological Model - Devdeep Sarkar
On large angular scales (greater than about 60 degrees), the two-point angular correlation function of the temperature of the cosmic microwave background (CMB), as measured (outside of the plane of the Galaxy) by the Wilkinson Microwave Anisotropy Probe, shows significantly lower large-angle correlations than expected from the standard inflationary cosmological model. Furthermore, when derived from the full CMB sky, the two lowest cosmologically interesting multipoles, the quadrupole (l=2) and t...
Downloads: 2
[texts]On the permutation modules for orthogonal groups $O_{m}^{\pm}(3)$ acting on nonsingular points of their standard modules - Jonathan I. Hall
We describe the structure, including composition factors and submodule lattices, of cross-characteristic permutation modules for the natural actions of the orthogonal groups $O_{m}^{\pm}(3)$ with $m\geq6$ on nonsingular points of their standard modules. These actions together with those studied in \cite{HN} are all examples of primitive rank 3 actions of finite classical groups on nonsingular points.
Downloads: 2
[texts]Final State Interactions in Decays of the Exotic $π_{1}$ Meson - Nikodem J. Poplawski
We analyze the role of final state interactions in decay of the lighest exotic meson, $pi_1$ with $J^{PC}=1^{-+}. We use the relativistic Lippmann-Schwinger equation for two coupled $\pi b_{1}$ and $\pi\rho$ channels. The first one is the predicted dominant decay mode of the $\pi_{1}$, whereas in the other a narrow $\pi_1(1600)$ exotic signal has been reported by the E852 collaboration. The FSI potential is constructed, based on the $\omega$ meson exchange between the two channels...
Downloads: 2
[texts]Two-dimensional QCD and instanton contribution - A. Bassetto
In these notes Yang-Mills theories in 1+1 dimensions are reviewed. Instantons on a sphere prove to be -in the decompactification limit- the key issue to clarify an old controversy between equal-time and light-front quantization.
Downloads: 2
[texts]Some observations on a Kapteyn series - Diego Dominici
We study the Kapteyn series $% %TCIMACRO{\dsum \limits_{n=1}^{\infty}}% %BeginExpansion {\displaystyle\sum\limits_{n=1}^{\infty}} %EndExpansion t^{n}\mathrm{J}_{n}(nz) $. We find a series representation in powers of $z$ and analyze its radius of convergence.
Downloads: 2
[texts]arxiv-astro-ph0503063
[texts]Study of the composition of products of controlled nucleosynthesis by local auger-electron spectroscopy - S. V. Adamenko
By local Auger-electron spectroscopy on solid targets and accumulating screens, we studied the composition of nucleosynthesis products, in which we expected to reveal the presence of long-lived transuranium elements (LTE). In a number of cases for analyzed elements in complicated spectra the Auger-spectra of corresponding pure elements or their simple compounds were registered with a high signal-to-noise ratio...
Downloads: 3
[texts]Search for a Massive Di-photon Resonance at sqrt{s} = 91-172 GeV - The OPAL Collaboration
A search for the resonant production of high mass photon pairs associated with a leptonic or hadronic system has been performed using a total data sample of 25.7 pb^-1 taken at centre-of-mass energies between 130 GeV and 172 GeV with the OPAL detector at LEP. The observed number of events is consistent with the expected number from Standard Model processes. The observed candidates are combined with search results from sqrt{s} ~ M_Z to place limits on Br(H^0 -> gamma gamma) within the Standard Mo...
Downloads: 1
[texts]Fermi-LAT data reprocessed with updated calibration constants - J. Bregeon
Four years into the mission, the understanding of the performance of the Fermi Large Area Telescope (LAT) and data analysis have increased enormously since launch. Thanks to a careful analysis of flight data, we were able to trace back some of the most significant sources of systematic uncertainties to using non-optimal calibration constants for some of the detectors. In this paper we report on a major effort within the LAT Collaboration to update these constants, to use them to reprocess the fi...
Downloads: 2
[texts]On the Consistency of the Exact Renormalization Group Approach Applied to Gauge Theories in Algebraic Non-Covariant Gauges - Michele Simionato
We study a class of Wilsonian formulations of non-Abelian gauge theories in algebraic non-covariant gauges where the Wilsonian infrared cutoff $\Lambda$ is inserted as a mass term for the propagating fields. In this way the Ward-Takahashi identities are preserved to all scales. Nevertheless BRST-invariance in broken and the theory is gauge-dependent and unphysical at $\Lambda\neq0$. Then we discuss the infrared limit $\Lambda\to0$...
[texts]Properties of a thin accretion disk around a rotating non-Kerr black hole - Songbai Chen
We study the accretion process in the thin disk around a rotating non-Kerr black hole with a deformed parameter and an unbound rotation parameter. Our results show that the presence of the deformed parameter $\epsilon$ modifies the standard properties of the disk. For the case in which the black hole is more oblate than a Kerr black hole, the larger deviation leads to the smaller energy flux, the lower radiation temperature and the fainter spectra luminosity in the disk...
Downloads: 2
[texts]Spontaneous magnon decays in planar ferromagnet - V. A. Stephanovich
We predict that spin-waves in an easy-plane ferromagnet have a finite lifetime at zero temperature due to spontaneous decays. In zero field the damping is determined by three-magnon decay processes, whereas decays in the two-particle channel dominate in a transverse magnetic field. Explicit calculations of the magnon damping are performed in the framework of the spin-wave theory for the $XXZ$ square-lattice ferromagnet with an anisotropy parameter $\lambda
Downloads: 1
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